N = int(input())
item_num = []
for i in range(N):
    array = list(map(int, input().split()))
    item_num.append(array)

item_cnt = [0] * 10

for i in range(N):
    for j in range(3):
        item_cnt[item_num[i][j] - 1] += 1

pow_up = 0
single = 0
for i in range(10):
    pow_up += item_cnt[i] // 2
    if item_cnt[i] % 2 != 0:
        single += 1

print(pow_up + single // 4)